bld2ff.c

#if 0
gcc -s -O2 -o ~/bin/bld2ff -Wno-unused-result bld2ff.c
exit
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int width,height,comp;

static void
usage(void)
{
	fprintf(stderr,
		"Usage: bld2ff                                                                 \n"
		"                                                                              \n"
		"Convert MegaPaint BLD image to farbfeld. bld2ff reads a BLD image from stdin, \n"
		"converts it to farbfeld and writes the result to stdout.                      \n"
		"                                                                              \n"
		"MegaPaint BLD is the main native raster graphics format of MegaPaint, a legacy\n"
		"graphics program that was released for the Atari ST, MS-DOS and Windows.      \n"
		"                                                                              \n"
		"The program takes no arguments.                                               \n"
		"                                                                              \n"
		"Example usage:                                                                \n"
		"   $ bld2ff < image.bld > image.ff                                            \n"
		"   $ bld2ff < image.bld | bzip2 > image.ff.bz2                                \n"
		"\n"
	);
	exit(1);
}

static void
do_byte(int c)
{
	static const char s[]="\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\0\0\0\0\0\0\xFF\xFF";
	static int x=0;
	int n=x<width-8?8:width-x;
	if (n>=width-8) x=0;
	while(n--) {
		fwrite(s+(c&128?8:0),1,8,stdout);
		c<<=1;
	}
}

int
main(int argc, char **argv)
{
	int c, n;

	if (argc > 1) {
		usage();
	}

	width = fgetc(stdin)<<8;
	width |= fgetc(stdin);
	height = fgetc(stdin)<<8;
	height |= fgetc(stdin);
	if (width & 0x8000) {
		width=0x10000 - width;
		comp=1;
	}
	++width;
	++height;
	fwrite("farbfeld\0",1,10,stdout);
	putchar(width>>8);
	putchar(width);
	putchar(0);
	putchar(0);
	putchar(height>>8);
	putchar(height);
	while (height && (c=fgetc(stdin))!=EOF) {
		do_byte(c);
		if (comp && (c==0 || c==255)) {
			n=fgetc(stdin);
			if (n>0) while (n--) do_byte(c);
		}
	}
	return 0;
}